STEAM has encountered an error and needs to close

[bullzi]

yea, its crashing, just got my new 300gig HD, works great, got xp home up and running sp2 with every possible update installed, all updated drivers for everything, but whenever i try to run STEAM it says connecting to account "BullziSnipr" (me obviously) and then the crash window pops up and says "STEAM has encountered an error and needs to close", ive updated steam, reinstalled steam, nothing works, and of course they dont have this on their website, whats the problem????